Machine for angular grinding spectacle glasses



0'. HENKER. MACHINE FOR ANGULAR GRINDING SPECTACLE GLASSES.

APPLICATION FILED AUG. I3, 1921.

Z 2. 9 I 4 1 R a M d m m D T E E H A s T .E E H s 2 0. HENKER.

MACHINE FOR ANGULAB GRINDING SPECTACLE GLASSES.

APPLICATION FILED AUG. I3. 1921.

Patented Mar. 14, 1922.

'2 SHEETS-SHEET 2.

4 K Ari/l m u NIT Eaowe-Hartman, on June, GERMANY, ASSIGN'OR TO THE FIRM or CARL ZEISS, OF JENA,

FFECGE. v

LGERMAN'YL MAcHInn Eon ANGULAR GRINDING srnc'r ionnenassns,

Specification of Letters Iiatent. 14s,

Application filed August 13, 1921: sriai'na-isaisa."

a glass in which; a cro ss-section through cylindrical surface passing; through the glass-rim, the straight lines on this surface being parallel-to the axis of the glass, forms an ellipse for instance. ,Qn the sha-ft-ot this machine, Which carriesthe vglass, which rotates on being ground, a plane cam is disposed. limiting the grinding by contacting w-ithwastop the-moment the desired grinding at the particularfpart o 't .thejrini-surface :be-

ing; operated upon is 'acconipl'i'shed-,- and this shatt may lie SW-uilg-fabou't' an -aX1s, j Wllittll intersects it perpendicul'arlyi and-which crosses the axis of, the grindstone perpendicularly. The: term angular edge denotes that line in which the two rim-surfaces intersect one another irrespective ofiwhether this line actually exists on-the spectacleglass itself or would only be formed beyond it. A machine of the above kind; has" hecome known through the German Patent 237190 Ecltsteiu- Aug? 29, 1911, However, whilstin this known-machine the stop reta-ins its position duringtheygrinding. op

eration, and the rain is rigidly fixed to the shattcarrying it. iii-the neuvmachine the stop is rotatable about -a: :is,-wl1icli is parallel to the axis of oscillationallnded to distance-from this axis, andivhich vlies iu the plane determ ned by this axis of oscillaand, in addition, the cams is displaceable longitudinally on its shaft; and by -means of the; stop compelled: to perm-anently conta-inin its plane the axistof rotationo-f-the stop ,.-on the shaft being revolved.

*In-- the annexeddrawings Fig, 1 shows partsi equation holds goodtion and the point which the' angi ilar;edge v has-:in common with the--grindi-ng. surface,

' diagrammatically an example of how a inaclnn'e according to the 'present'invention *in'ay' be arranged; F1gI2fshows-1n plan-a constructional exarnple of a machine accordmg to theanventioniof them'ore developed turnip-Fig; 3 sho'wsa vertical 'cross sectio'n, through a part of the machine *otFig; 2; Fig. tshmvs a vertical cross section throu h anothen part ofmthe" 'niachin'e of- Fig; 2, whereby in' Figs. 3 and iforthesake of- 1 cleanness; the relative' position: of certain schosen somewhat ditt'erentlyas compare'd'with'Fi'g. 2'.

The. d" tie-rent possibilities of arrangement of the" new ma'chine-u-Inay be elucidated, reference v-b'eing; had .to Fig- '1. of the drawmg. In :the said l figure the g ll'IlClSlL'OH-G" 1s marked A, -1ts ::aX1soif I Ot2tt1OI1, 1K. The spectacle-glass to he ground, =13, rotz'ijtes during; the grinding about an axis Y the glass is: shown ready ground.) Ci -indicates theqpoint:which theangular edge of the glass hasin common with the grinding surface. D signifies the axis which is perpendicularto the drawing-plane and about which the axis :YUY. may be swung; The

wh-ich u is perpendicular to the drawingplane, and parallel totlie axis ofoscillation is marked F. The point Flies, asis essential tor -the new machine, inra: straight.

line along with; (I andD. Thea cam, which permanently;contains ll'ljltS PlfiHG the/axis of rotation-F, and which is displaceable along the axis Y ,Y Qis marked G, the point in which itr contacts with the U stop E is l marked H and the pointiin which its plane f Not c191-v I For the carrying out of the new machine, .first of-all a special case arises.- 1 This 7 specialcase is characterized by the straight line i EHialwaysbeing zero, hence, by the point in 'which-the cam contactswiththe stop; in-

variably falling into the axis of rotation of the stop. The above ment oned equation then changes into the following equation:

glasses vary in size according to the chosen length of the straight lines CD and DF respectively, but approximate to the cam as regards their shape, and moreover, for this whole set one single cam will'suflice, quite independent of the median curvature of the, spectacle-glass to be ground, while by means of the machine described in the patent specification 237190 this approximation is obtained only inthe case of the median curvature of the spectacle-glass agreeing with that of the cam. If, however the machine, deviating from this special case, is arranged in such a manner that the straight line FH is variable as regards its length, thenfor every value of the fraction e set of spectacle-glasses is obtained which glasses vary in size according to the length of the straight line FH, but agree as regards their shape inasmuch as the fraction;%1 completely differ from one another, so that any glass out of one of the sets does not at the same time belong to anotherset. For that particular glass of every set for which FH is zero the machine corresponds to the special; case as dealt with above. Hence, the shape of this glass again approximates to the cam. Vith a machine arranged this way itis possible for instance (within certain limits given by the various 7' possibilities of adjustment of the machine) to complete by means of one single oval cam any oval spectacle glass of any median curvature,as long as, e. g., no, more is required than that the two main axes of this glass have certain definite values, or that the circumference of this glass has a certain definite value. In the case of the known machines, on the contrary, for every glass a special cam was required, if glasses having no symmetrical cross-section were dealt with.

About the values whichrin the case of a given cam and of a chosen value of the straight line CD have to be given to the straight lines DF and FH the following may be observed, by way of example for oval spectacle-glasses The radius vector C J of the spectacle-glass, Which happens to lie in pen to be perpendicular to the drawin I serving for 'fixing it.-

the drawing-plane, may be major semi-axis of the glass, and the radiusvector H I of thecam, which happens to lie in the drawing plane, the major semi-axis of the cam; the respective minor semi-axes, which happlane, may be marked CJ and H'I. As,

mentioned above- CJ J2- HI I FH T DF correspondingly I I our on EU +FH7W' In the case of a given cam, therefore H I and H J being given, of a chosen'value of C D, and of predeterminedaxes of the spec V V tacle-glass, therefore C J and C J being predetermined there results from the said equations As a matter of course the new machine, 1

although its proper significance lies in the grinding of non-circular spectacle-glasses,-

may as well be utilized'for grinding circularly shaped spectacle-glasses. If for-the grinding ofv such glasses the use of a special circular cam is to be avoided, any non-circular cam willdo, if releasably coupled to the shaft carrying the glass, so that when disengaged it takes no part inthe rotation of the shaft, and if this cam be fixable relatively to the stop. The fixed cam will then act thesame as a circular cam having a radius equal to that particular radius vector of the fixed cam with theend-point of which the camcontacts with the stop.

In Figs. 2 to 4 of the drawing the invention is illustrated by means of a jconstruc- .tional example, which represents a machine of the more developed form, i. e. none corresponding only to the special case as dealt with above;

A base-plate (i carries two bearings 0, and (L in which a shaft 6 carrying a grindstone bis supported. An electric motor a serves for driving' this grindstone; 'A bracket a fixed to the body of the'bearing a carries a table 03 which has the shape of a circular ring segment, the axis of the circu lar ring contacting with the convex surface of the'grindstone I); On' two sliding-sun faces (Z and d of this table a carriagee iis displaceably disposed, a clamping screws Between two guides e and e, which are fixed to the carriage e there is acarriage f 'displaceably disposed, a

clamping screw 7 serving for fixing it. To

l a stand f which is" fixed; to "oneend 'oflth-e carriage F, a bearingg is b-ythe" aid of a bolt 9 so -fitted th'a-t it-maybe swung about a vertical axis. On the other end er. the

- carriage-f aslidingsurface: f is provided,

having the shapeof a circular ring segment,

'thea-xis of 'theci rcular ring;coincidi-n=g with the axis of thebolt-g 'A- carriageg is: so

disposed as to=be-displaeeable longitudinally on' this sliding su-rface,- two stops a-nd'g limiting its} way.' A shaft: k intended for carrying on; one o-fits"endsvthe spectacleglassto beg-round; marked 1; (indicated: in

the 1 drawing in dotted lines) is at this end journall'ed in the bearing 9 and at its oth'er end, onqthe'oner hand;- supported a bushin the" lid g"- ofa casing which is carried bythe said? part Two }rings j and j prevent the-shaft h from being displaced in the bushing-1g; By' n eansof agkey .Lj-

which engages in agroove it" of the shaftih, this shafthas a worm-wheel 70? so fitted to it that it can befdis p laced relatively to the Worm-wheel; "A n eleetr'ie motor Z fixed to driving the" shat-1721: "bushing: m is by means of whey 7' engaging in the'groove h so, ,fitted' tothe" shaft-Mas to be} d-i'splaceable relativ'elyto this shaft-.- On the bushingm j thereis aplane elliptically shapedcam n ro-v tatabl-y,disposed; a nut m preventing it from beingdisplaced relatively --tothis bushing. A; screw m permi-tsof the-cain to be secured to the bushing, Between-two guides f an'd f", which are disposed'on the; carriage 7; ,an cl""which' .a1e parallel; to the guides 0 3 and 6 ,3. carriage 0 isfdisplaceably disposed,

a clamping-screw '0 servi ng-for fixing it.

" To this carriage a-slidingsurface 79 is rotatably fitted by the aidofa screw-bolt 37 the axis of which lies in the plane containing the'axis of the table d andthe axisof-the bolt g The sliding surface p carries two uides andl'p between which a carria'e P a g g 'is displaceably disposed; a'claniping screw 2 servinmforlfixin it? This carria e carries a stop 1 which embraces the cam 02 by means oftwo projections. g andgi' a screw permits of the c'a'm tobe' clampedon the stop. A weight r 'isby' meansof a cord N, which passes over a roller 1' which is supported by the stop fastened to a ring 9, which is fixed to the carriage g and under its action the 'cam nis pressed toward the stop 9 The position of the carriage e is indicated on a graduation s by means of an index 8", which indicates the value 180 in the case oi. the plane containing the axis of the bolt and that of the sc-rewebolh 192* being. .1 parallel to I the straight lines on the, convexzsurfaceof the adranceswfron the;1.80-(hvisionsto; either side -]n the reverse sense,1n' sucha manner-that the difference between any'two figures: isas big again as the corresponding angular difference.- Three graduations.-tj, 'u'and w and three indices t n and o 'serve for indicating the position .1 of the carriagesa f}, v0 and mg} respectively; on the graduation e that particular division 20 is: rendered conspicuous at which the index o points in the case of the axiseofi-t'he bolt falling into that surface of the stop g which faces the cam. About the manipulation, of the. new; machine the following may be observed with reference to the constructional example. The spectacle-glass ilhaving been cemented onto. the headiof the shaft .h, ,byturningthe;

mil ledjhead'fl the: shaft fil'is soset inlthe direction of itsmaxis'l thatftheidistanc'e apart of the spectacle-glass andj'th e b'olt g iiis smaller. than. the-radius of the weaker curved limitin -surface of .Lthe glass and larger than the, radius i-Qf, the stronger euryedjliniiting surface of :thegglassdand the carriage f is so Set that the g esslr o ives P11111 1 .9"

sition relatively to the "'g'rindsconerFr-m thermore, the'eain a is, to be clamped on'thev bushing m by the aid; o'fthe screw mfland the screw 9 is to be released. The carriages 0 and g are then so to be set that"the -distance of the axis of'the screw-bolt p from the axis of the bolt g and the displacement: of the carriage 9} out of thatv position in "Which-the index I)O points) at the division to of the graduation a -receive: those respective values-previouslylaseertainechfor the straight lines DE and FH: ofv Fign-l which. correspond to: the semi-axes -o-f'tthe camand tortihe desired semi-axes of .the'speetacleeglass. At

last the carriage e is so to be set? ithat'the index 8 'indicateskoni the I graduationasa that angle (in e the exampleof: the :drawingan;

a-ngle of which: is to be forniedxbyzthe t-Wdrim-surfaces 0t ithe glass; to--eaclrangle belong two divisions on the t graduation s,

one for-the one rim surface and the' .otherifor the second grim-surface; V The: COIlStIIlCtlOllill example of thedrawing'showing the angular grinding; of the spectacle-glass a completed, it 'w'ould haye to'be assumedatliat the-grind ing oft'h e rim surfacenvhich ini the drawing happensto-Jbe contacting. withthe grindstone had; been preceded by the grinding ofathe other rim-surface, namely, in that position of the carriage e in which'the index had, pointed atthe other 120-division.

When the carriage e is so set that the index 8 points at the (only) -division of shape of which is similar to the cam, the

position of the carriage 9 must be such that the index '0 points at the division 'w of the graduation 'v. The position of the carriage f is again to be ascertained by the aid of the equationv 7 Hl HI DF M which may be substituted by the equation-- In this equation Z signifies the value of the ratio of the radii vectors of thespectacleglass to those of the cam; hence a HI Hl' When, without changing the cam, a circular spectacle-glass is to be ground by means of the machine shown in the drawing, the screw m has to be released, andthe cam n, in any desired place thereof, has to be secured to the stop 9 by means of the screw g, the carriage g having-any desired posiand H51 that particular radius vector of the cam with the end-point of: which the contacts with the stop.

I claim: r

1. Ina. machine intended for-angular grinding spectacle-glasses of non-circular shape, a plane cam, a stop,,a grindstone, and a shaft designed for holding the spectacle cam glass, the said cam cooperating with the stop and being disposed on the said shaft, which is free to oscillate aboutan axis by which it is intersected perpendlcularly and the axis of the grindstone crossed perpendicularly, the saidstop being rotatable about an axis, which is parallel to the axis of oscillation of said shaft and. at a variable dis- 'tance from it,and whichlies in the plane sto determined by the said axis of oscillation and by the point which the angular edge of the spectacle-glass has in common with the the stop, on the said shaft being rotated. 1

2. In a machine intended ,for angular grinding spectacle-glasses of non-circular shape, a plane cam, a stop, agrindstone, and a shaft designed foriholding the spectacleglass, the said cam co-operating with the andbeing disposed on the said shaft,

which is free-to oscillate about an axis by which it is intersected perpendicularly and the axis of the grindstone crossed perpendicularly, the said stop beingrotatable about an axis, which is parallel to said axis of oscillationof saidshaft and at a ,variable o distance from it, and which lies in the plane determined by the saidaxis of, oscillation and. by the point which the angular edgeof the spectacle-glasshas in common with the grinding surface, the *said cam being dis-q -placeable longitudinally on-its shaft and beingjcompelled by the stop to permanently contain in' itsiplane the'axis of rotation of the stop, on the said shaft being rotated.

3. In a machineflintended for angulan grinding spectacle-glasses of non-circular shape, a planecam, a stop, aigrmdstone, and

a shaft designedfor holding the spectacleglass, the saidcam co-operating with the that it may be uncoupled from it andvfixed relatively to the stop, the said shaft being free to'oscillate about an axis by which it-is intersected perpendicularly and the axis of the grindstone crossedperpendicularly, the said stop being rotatable about an axis, which is parallel tothe axis: of oscillation of said shaft and ate variable distance from it, and which'lies in the plane determined by the said axis of oscillation and by the point which the angular edge of the spectacle-glass has in common with the grinding surface, the said cam being displaceable longitudinallyon its shaft and being compelled by the stop to permanently contain in its plane the axis of rotation of the stop,

.stop and beingdisposed on the said shaft so.- 

